1. Field of the Art
The present invention relates to an ice thermal storage refrigerator unit and, more particularly, to an ice thermal storage refrigerator unit which may be used in an air conditioning facility for an ordinary building, or the like.
2. Prior Art
An ice thermal storage refrigerator unit has been developed as a cooling system that utilizes the midnight service of electricity, which is economical, and it has been used as an energy-saving and space-saving building cooling system.
A typical ice thermal storage refrigerator unit includes a brine path consisting of a refrigerator, an ice thermal storage tank, a water heat exchanger, a brine pump, and control valves, which are connected by piping, and a cold water path consisting of the water heat exchanger, a cooling load, and a cold water pump, which are connected by piping. Brine is cooled in the refrigerator, and used to freeze water in the ice thermal storage tank, thereby storing heat (in this case negative) in the ice thermal storage tank. When heat is to be discharged, the brine is cooled by means of fusion heat of the ice contained in the ice thermal storage tank, and the brine is introduced into the water heat exchanger to cool cold water, thereby supplying cooling power to the cooling load.
In a conventional ice thermal storage refrigerator unit, however, load measurement and load prediction have heretofore been made by using advanced computer technology, and complicated and costly control has been required.
Further, in a conventional refrigerator unit, a refrigerator is mainly used and a thermal storage tank is only used as an auxiliary device. Accordingly, the cooling capacity of the thermal storage tank is not used to the fullest extent, which necessitates costly operation of the refrigerator during daytime and increases machine capacity.
Therefore, an object of the present invention is to solve the above-described problems and to provide an energy-saving and low-cost ice thermal storage refrigerator unit which enables a thermal storage tank to be effectively used to the fullest extent with only the use of a simple measuring instrument.